A computer-aided design (“CAD”) system is a computer implemented tool for engineers and architects to utilize in designing different structures from products to buildings. A similar system, called a computer-aided manufacturing or machining (“CAM”) system, is a computer-implemented tool for making design changes to a model and manufacturing or machining the model. The computer portion of the CAD/CAM system conventionally includes a central processing unit, a display device, such as a computer monitor, and a number of input devices such as, a keyboard, a mouse, a light pen, a digitizing tablet, and the like. The central processing unit typically has one or more CAD/CAM software applications installed thereon.
The CAD/CAM software applications allow a user to input and view a design for a particular structure in the form of an object. Each object in a design is often referred to as a design object. The user can often rotate the view of the object to any angle, and also zoom in or zoom out for different views and perspectives. Additional visual features such as highlighting, shading, cross-hatching, and the like, enable the user to design an object with the aid of the computing power inherent in the central processing unit. The CAD/CAM application can also keep track of, and monitor, design changes to the object in addition to design dependencies. This means that when the user adds or changes an element within the object, other values that depend on that change are automatically updated in accordance with engineering concepts and rules of design.
In a number of applications of the CAD/CAM systems, there is often the likelihood that one or more of the objects being modeled has flexible characteristics, or otherwise varying properties. For example, compressible, expandable, bendable, and twistable parts (either individual components or units formed by a number of individual components) may experience a certain amount of flexing, or other changes, as the part is utilized in a larger system. Depending on loads being applied to the parts, materials such as metal, wood, composite, and the like, are designed to flex or change dimension a predetermined amount as the system or device in which the part is installed operates. In addition, other physical changes may result from thermal variations of the parts caused by mechanical action or environmental changes.
In designing devices or systems, there is often the desire to purchase a part from another manufacturer and insert the part into the device or system being designed. For example, if an engineer is designing an automobile, the engineer may wish to purchase the shock absorbers from another manufacturer, rather than create a completely new shock absorber. Such an object, viewed from the enterprise viewpoint, can be referred to as a business object. A business object is any item or product that must be tracked during the life of that project. Because the shock absorber is purchased from a supplier, the entire shock absorber is a single design object in CAD/CAM terminology, and a business object from the viewpoint of an enterprise system. Business objects do not have to be design objects, but can also be other trackable items, such as written documentation or marketing material.
Returning to the flexible objects, it is often necessary to model the flexible object in a plurality of different states to represent how the flexible object interacts with other components and objects in the device or system being modeled. More specifically, returning to the shock absorber example, as the shock absorber experiences a load applied along its axis the shock absorber will compress to absorb the load. As the load is removed, the shock absorber will expand. When the shock absorber is in a compressed state, the overall length of the shock absorber is less than when the shock absorber is in an uncompressed, or marginally compressed, state.
Conventional CAD/CAM applications have approximated the flexible characteristics of such parts as shock absorbers by creating multiple CAD/CAM objects. Each object represents a different state of flex, or in the instance of the shock absorber, a different state of compression. More specifically, the shock absorber may require three or more CAD/CAM objects to be sufficiently represented. A first object represents the shock absorber in a less compressed, or normally loaded, state. A second object represents the shock absorber in a partially compressed state, such as in a fully loaded automobile. A third object represents the shock absorber in a fully compressed state, such as the instant when the fully loaded automobile hits a speed bump. Each of these states can be important in designing the coupling of the shock absorber to other components within the suspension system of the automobile, and their subsequent interaction during the different states of compression as the flexible characteristics of the shock absorber vary.
However, if the flexible object is also a business object, each instance of the object often must be tracked. Therefore, creating a plurality of objects to represent the flexible object in a plurality of states of flex can create difficulties when trying to track the business objects in the system. The system, or the engineer, must make determinations as to which object to track as a business object, and which object is merely a different instance of a previously existing business object. Additional time and resources must be devoted to making these determinations and tracking the appropriate objects of the resulting product.
In addition, some conventional CAD/CAM systems require the engineer to physically create each additional object to show different flex states of a flexible object. The added steps decrease the efficiency of the design process, and therefore increase costs.
Therefore, a need exists for a CAD/CAM application that can represent the same design object in an assembly, system, product, etc., with varying occurrences (i.e., variations of flexible characteristics or properties) and without the creation of additional business objects to represent these occurrences.